Suspension damper with by-pass valves

ABSTRACT

A vehicle damper is described. The vehicle damper includes: a cylinder; a piston within the cylinder; a working fluid within the cylinder; a reservoir in fluid communication with the cylinder via the working fluid, the reservoir operable to receive the working fluid from the cylinder in a compression stroke; a valve in a flow path between the cylinder and the reservoir; and a remotely-operable valve having a position allowing the working fluid to significantly by-pass the valve.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of and claims priority toand benefit of U.S. patent application Ser. No. 16/786,316, filed onFeb. 10, 2020, entitled “SUSPENSION DAMPER WITH BY-PASS VALVES” by JohnMarking, and assigned to the assignee of the present application, whichis herein incorporated by reference.

The application Ser. No. 16/786,316 is a continuation application of andclaims priority to and benefit of U.S. patent application Ser. No.15/418,322, filed on Jan. 27, 2017, now Issued U.S. Pat. No. 10,556,477,entitled “SUSPENSION DAMPER WITH BY-PASS VALVES” by John Marking, andassigned to the assignee of the present application, which is hereinincorporated by reference.

The application Ser. No. 15/418,322 is a continuation-in-partapplication of and claims priority to and benefit of U.S. patentapplication Ser. No. 13/750,336, filed on Jan. 25, 2013, now Issued U.S.Pat. No. 9,556,925, entitled “SUSPENSION DAMPER WITH BY-PASS VALVES” byJohn Marking, and assigned to the assignee of the present application,which is herein incorporated by reference.

The application Ser. No. 13/750,336 claims priority to and benefit ofU.S. Patent Application No. 61/590,577 filed on Jan. 25, 2012 entitled“SUSPENSION DAMPER WITH BY-PASS VALVES” by John Marking, and assigned tothe assignee of the present application, which is herein incorporated byreference.

This application is related to U.S. Provisional Patent Application No.61/366,871 filed on Jul. 22, 2010 entitled “LOCK-OUT VALVE FOR ASUSPENSION DAMPER” by John Marking, assigned to the assignee of thepresent application, which is herein incorporated by reference and U.S.Provisional Patent Application No. 61/381,906, filed on Sep. 10, 2010entitled “REMOTELY ADJUSTABLE SUSPENSION DAMPER” by John Marking,assigned to the assignee of the present application, which is hereinincorporated by reference. This application is related to U.S.Provisional Patent Application No. 61/366,871, and corresponding U.S.patent application Ser. No. 13/189,216 filed on Jul. 22, 2011 entitled“SUSPENSION DAMPER WITH REMOTELY-OPERABLE VALVE” by John Marking, nowU.S. Pat. No. 9,239,090, assigned to the assignee of the presentapplication, each of which is incorporated entirely herein by reference.

This application is also related to U.S. patent application Ser. No.13/010,697 filed on Jan. 20, 2011 entitled “REMOTELY OPERATED BYPASS FORA SUSPENSION DAMPER” by John Marking, now U.S. Pat. No. 8,857,580,assigned to the assignee of the present application, which is hereinincorporated by reference and claims priority to and benefit of U.S.Provisional Patent Application No. 61/296,826 filed on Jan. 20, 2010entitled “BYPASS LOCK-OUT VALVE FOR A SUSPENSION DAMPER” by JohnMarking, assigned to the assignee of the present application, which isherein incorporated by reference. U.S. patent application Ser. No.13/010,697 is a continuation-in-part application of and claims priorityto and the benefit of U.S. patent application Ser. No. 12/684,072 filedon Jan. 7, 2010 entitled “REMOTELY OPERATED BYPASS FOR A SUSPENSIONDAMPER” by John Marking, and assigned to the assignee of the presentapplication, and is herein incorporated by reference, which claimspriority to and benefit of U.S. Provisional Patent Application No.61/143,152 filed on Jan. 7, 2009 entitled “REMOTE BYPASS LOCK-OUT” byJohn Marking, assigned to the assignee of the present application, whichis herein incorporated by reference. This application is also related toU.S. patent application Ser. No. 12/684,072 filed on Jan. 7, 2010entitled “REMOTELY OPERATED BYPASS FOR A SUSPENSION DAMPER” by JohnMarking, and assigned to the assignee of the present application, and isherein incorporated by reference, which claims priority to and benefitof U.S. Provisional Patent Application No. 61/143,152 filed on Jan. 7,2009 entitled “REMOTE BYPASS LOCK-OUT” by John Marking, assigned to theassignee of the present application, which is herein incorporated byreference. This application is also related to U.S. patent applicationSer. No. 13/175,244 filed on Jul. 1, 2011 entitled “BYPASS FOR ASUSPENSION DAMPER” by John Marking, now U.S. Pat. No. 8,627,932,assigned to the assignee of the present application, which is hereinincorporated by reference, which claims priority to and the benefit ofU.S. Provisional Patent Application No. 61/361,127 filed on Jul. 2, 2010entitled “BYPASS LOCK-OUT VALVE FOR A SUSPENSION DAMPER” by JohnMarking, and assigned to the assignee of the present application, and isherein incorporated by reference.

The technologies disclosed herein may be used in suitable combinationwith any or all of the technologies disclosed in the foregoing relatedpatent applications.

BACKGROUND

Embodiments of the invention generally relate to a damper assembly for avehicle. More specifically, certain embodiments relate to valves used inconjunction with a vehicle damper.

Vehicle suspension systems typically include a spring component orcomponents and a dampening component or components. Typically,mechanical springs, like helical springs, are used with some type ofviscous fluid-based dampening mechanism and the two are mountedfunctionally in parallel. In some instances features of the damper orspring are user-adjustable. What is needed is an improved method andapparatus for varying dampening characteristics.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates a section view of a suspension damper, in accordancewith an embodiment.

FIG. 1B illustrates a section view of a suspension damper, in which thedamper piston of the suspension damper is moving in a compressionstroke, in accordance with an embodiment.

FIG. 2A illustrates a section view of a suspension damper, in accordancewith an embodiment.

FIG. 2B illustrates a section views of the reservoir 140 showing valvesof the valve assembly in various positions during a compression strokeof the damper, in accordance with an embodiment.

FIGS. 3A and 3B show an example intensifier piston (as described andshown in U.S. Pat. No. 7,374,028) of a pressure intensifier damperarrangement, in accordance with an embodiment.

The drawings referred to in this description should not be understood asbeing drawn to scale unless specifically noted.

DESCRIPTION OF EMBODIMENTS

Reference will now be made in detail to embodiments, examples of whichare illustrated in the accompanying drawings. While the technology willbe described in conjunction with various embodiment(s), it will beunderstood that they are not intended to be limited to theseembodiments. On the contrary, the present technology is intended tocover alternatives, modifications and equivalents, which may be includedwithin the spirit and scope of the various embodiments as defined by theappended claims.

Furthermore, in the following detailed description, numerous specificdetails are set forth in order to provide a thorough understanding ofembodiments. However, embodiments may be practiced without thesespecific details. In other instances, well known methods, procedures,components, and circuits have not been described in detail as not tounnecessarily obscure aspects of embodiments.

The discussion that follows will describe the structure andfunctionality of embodiments.

As used herein, the terms “down,” “up,” “downward,” “upward,” “lower,”“upper” and other directional references are relative and are used forreference only. FIGS. 1A and 1B are a section view of a suspensiondamper 100. The suspension damper 100 includes a cylinder portion 102with a damper rod 107 and a damper piston 105. In one embodiment, fluidmeters from one side of the damper piston 105 to the other side bypassing through flow paths (at least one flow path) formed in the damperpiston 105. In the embodiment shown, shims (at least one shim) are usedto partially obstruct flow paths through the damper piston 105 in twodirections. By selecting shims having certain desired stiffnesscharacteristics, the dampening effects caused by the damper piston 105can be increased or decreased and dampening rates can be differentbetween the compression and rebound strokes of the damper piston 105.

In FIG. 1B, the damper piston is moving in a compression stroke (asshown by directional arrow 117) with the damper rod 107 and damperpiston 105 moving further into the compression portion 104 and causingfluid to flow from a compression portion 104 to a rebound chamber 135 ofthe rebound side of the cylinder portion 102 via flow paths 112 and 111.Note that damper piston apertures (not shown) may be included in planesother than those shown (e.g. other than apertures used by paths 111 and112) and further that such apertures may, or may not, be subject to theshims as shown (because for example, the shims may be clover-shaped orhave some other non-circular shape). In one embodiment, the damperpiston 105 is solid and all damping flow must traverse a flow bypass(e.g. as shown in FIG. 2A space 150 between cylinder 102 and inner wall151 within the cylinder 102) and/or communicate with a reservoir.

As shown in FIG. 1B, compression stroke flow may traverse the damperpiston 105 via a first flow path 112 (e.g., an in board flow path)and/or via a second flow path 111 (e.g., an out board flow path). Thesecond flow path 111 is unrestricted and allows by-pass so that thedamper piston may travel more freely in compression. The first flow path112 is restricted by shims and provides more rigid compression dampingflow (hence suspension movement).

The compression portion 104 is partially defined by the first side 177of the piston 105. The rebound chamber 135 is partially defined by thesecond side 179 of the piston 105.

A by-pass shut off valve 120 is located toward an end of the compressionportion 104 of cylinder 102 and is biased away from that end by spring122. During a compression stroke the damper piston 105 moves toward theby-pass shut off valve until the surface 121 abuts a radially outerportion of leading surface 126 of damper piston 105. When such abutmentoccurs the annular surface 121 covers all by-pass ports 111 (flow path111) located along the outer edge of the damper piston 105 therebyclosing off the compression fluid bypass through those ports. Remainingcompression fluid must traverse the damper piston 105 via ports 112where that fluid will be subject to restriction of the compressionshims. Following contact with the ring of the by-pass shut off valve 120further movement of damper piston 105 compresses spring 122 therebyallowing the ring of the by-pass shut off valve 120 to move with thedamper piston 105 toward the end of the compression stroke.

In FIG. 1A, the damper piston is moving in a rebound stroke (oppositethat shown by directional arrow 117 of FIG. 1B) with the damper rod 107and damper piston 105 moving further out of the compression portion 104and causing fluid to flow from a rebound chamber 135 of the rebound to acompression portion 104 of the cylinder portion 102 via flow paths 110A,110B, and 109. Note that damper piston apertures 109 may be included inplanes other than those shown (e.g. other than apertures used by paths110 and 109) and further that such apertures may, or may not, be subjectto the shims as shown (because for example, the shims may beclover-shaped or have some other non-circular shape). In one embodiment,the damper piston 105 is solid and all damping flow must traverse a flowbypass (e.g. as shown in FIG. 2A, space 150 between cylinder 102 and theinner wall 151 within the cylinder 102) and/or communicate with areservoir.

In the embodiment of FIG. 1A, fluid within rebound chamber 135 fluidflows into flow paths 110 (first set of radially outward directed paths)as the damper rod 107 moves outward from cylinder compression portion104. Rebound flow moves from paths 110 to a central flow path within thedamper rod 107 and then to one or more (a second set) radially outwarddirected paths 109 which traverse shim valves before opening intocompression chamber 104. The rebound fluid flow is thereby at leastpartially restricted by the shims although such restriction may beminimal or non-existent if the shims are not present or are by-passed.

When the rebounding damper rod 107 has moved outward far enough, theflow paths (ports or apertures) 110 reach shut off valve (first shut offvalve) 130. As ports 110A are covered by an inner diameter of shut offvalve sleeve 130 (first sleeve), rebound fluid flow there through iscorrespondingly shut off. Rebound fluid flow is substantially closedwhen further movement of damper rod 107 places ports 110B under sleeve130. The sequential closing of the ports 110A and 110B facilitates agradual increase in rebound damping with damper rod position duringrebound stroke. It is noted that axially displaced port sets 110A and110B are exemplary and that more axially displaced port sets may belocated at distances along the damper rod 107 to increase the sequentialincrease of the damping function. It is also noted that the damper rod107 may be extended further out of the compression side of the damperpiston 105 and such extension may include radially situated axiallyspaced flow ports like 110A and 110B which would engage with an innerdiameter of a sleeve like shut off valve sleeve 130 in place of the ringof the by-pass shut off valve 120 to create a sequential damping by-passreduction during a compression stroke.

In the embodiment of FIG. 2A, the damper includes an annular bypassformed between a wall of cylinder portion 102 and an inner wall 151having a slightly smaller diameter than the cylinder wall. In thismanner a space 150 is provided between the walls. (In one embodiment,the space 150 is annular.) In one embodiment, at least one port throughwall 151 on the compression side of the cylinder and another portthrough wall 151 on the rebound chamber 135 of the rebound side permitworking fluid to pass between the compression portion 104 and therebound chamber 135 of the rebound side without moving through theshimmed paths provided by the damper piston 105. The bypass feature isutilized so long as the damper piston is between the two ports in eitherthe compression or rebound strokes.

The lower portion of the damper rod 107 is supplied with a bushing set155 for connecting to a portion of a vehicle wheel suspension linkage.An upper portion of the cylinder portion 102 may be supplied with aneyelet 108 to be mounted to another portion of the vehicle, such as theframe, that moves independently of the first part. A spring member (notshown) is usually mounted to act between the same portions of thevehicle as the damper. As the damper rod 107 and damper piston 105 moveinto cylinder portion 102 (during compression), the damping fluid slowsthe movement of the two portions of the vehicle relative to each otherdue, at least in part, to the incompressible fluid moving through theshimmed paths provided in the damper piston 105 and/or through themetered bypass. As the damper rod 107 and damper piston 105 move out ofthe cylinder portion 102 (during extension or “rebound”) fluid metersagain through shimmed paths and the flow rate and corresponding reboundrate may be controlled, at least in part, by the shims.

A reservoir 140 is in fluid communication with the damper cylinder 102for receiving and supplying damping fluid as the damper piston damperrod 107 moves in and out of the cylinder portion 102 thereby variablydisplacing damping fluid. The reservoir 140 includes a cylinder portionin fluid communication with the compression portion 104 of the dampercylinder portion 102 via a fluid conduit 10 which houses a fluid pathbetween the components. The reservoir 140 also includes a floatingdamper piston 141 with a volume of gas in a gas portion on a backside(“blind end” side) of it, the gas being compressible as a damping fluidportion 132 of the cylinder of the reservoir fills with damping fluiddue to movement of the damper rod 107 into the damper cylinder 102. Thepressure of gas in the reservoir can be adjusted with compressed airintroduced through a gas valve located at a lower end of the reservoircylinder. Certain features of reservoir-type dampers are shown anddescribed in U.S. Pat. No. 7,374,028, which is incorporated herein, inits entirety, by reference. In one embodiment the damper includes anin-line reservoir (e.g. floating damper piston and gas charge) ratherthan a remote reservoir as shown in the Figures. The principlesdisclosed herein are equally applicable in either case.

In one embodiment, the damping characteristics of the damper are alteredby at least one valve that regulates flow between the compressionchamber 104 and the fluid portion 132 of the reservoir 140. In theparticular embodiment shown a reservoir valve assembly includes valves210 a, 210 b, and 220, each of which (monitors) permits, prevents orimpedes fluid flow into the reservoir fluid portion 132. The valves 210a, 210 b, and 220 are shown in more detail in FIGS. 1A, 1B, 2A and 2B.FIG. 2B shows section views of the reservoir 140 showing valves of thevalve assembly in various positions during a compression stroke of thedamper.

In one embodiment, the reservoir valve assembly is attached at an upperend of the cylinder portion of the reservoir 140 and serves to seal thefluid portion 132. Valves 210 includes a pathway leading from the fluidconduit 10 into the fluid portion 132 of the reservoir. One or both ofvalves 210 a and 210 b includes shims (a first set of shims [wherein thefirst set includes one or more shims]) functionally like those used indamper piston 105 and designed to offer predetermined resistance tofluid flow passing into the reservoir 140 during compression of thedamper. Another set of shims (a second set of shims [wherein the secondset includes one or more shims]) of valves 210 a and 210 b meter theflow of fluid out of the fluid portion 132 of the reservoir 140 during arebound stroke of the damper. The flow of fluid into and through valves210 during a compression stroke is shown by arrows. As shown, the flowof fluid has un-seated shims to permit the flow of fluid into the fluidportion 132.

In one embodiment, the reservoir also includes a remotely-operable valve220 and includes a movable plunger 222 that is substantially sealable ona seat 225. In FIG. 2B the valve 220 is open with a fluid path therethrough shown by an arrow. While FIG. 2B shows both all valves open andfluid flow by-passing valve 210 a, it will be understood that dependingupon the design of the system, including the selection of shims, valve210 a could remain closed and fluid might flow only through valve 220that is open or alternatively fluid may flow through both valve 210 aand valve 220 simultaneously albeit in selected proportions.

In FIG. 2A remotely-operable valve 220 is shown in a closed positionwith the plunger 222 seated upon seat 225. In the embodiment shown, thevalve 220 is shifted between an open and closed position by a solenoidlocated adjacent the valve and capable of receiving an electrical signaland causing the mechanical movement of the plunger 222. In oneembodiment, the solenoid operates in a “stepper” manner havingselectable stroke (e.g. based on electric signal input) that partiallycloses or partially opens the valve 220, thereby permitting orrestricting flow without completely opening or closing the valve (e.g.as in an infinitely variable throttle operating between absolute openand absolute closed positions).

In one embodiment (shown in Figures), the solenoid valve (whichalternatively may be operated by hydraulic cylinder) modulates flowthrough and around valve 210 a while flow through valve 210 b occursunder all circumstances. As such, valve 210 b provides a positive “base”damping resistance regardless of whether compliant damping (valve 220open) or more rigid damping (valve 220 closed) is selected. Suchpositive base damping helps the damper avoid cavitation during extremelyrapid compression.

In one embodiment, the solenoid-operated valve 220 is normally open (asshown in FIG. 2B) with working or damping fluid permitted to flowthrough both valves 210, 220 of reservoir. In the early portion of thecompression stroke, additional fluid may also bypass the shims of damperpiston 105 due to the space 150 (e.g., an annular bypass) with its ports(FIG. 2A). The foregoing configuration describes a “compliant” dampingmode with reduced dampening which is suitable for “plush” shockabsorption. Such mode may also allow a so-equipped vehicle to pitch orroll during braking or cornering respectively however. As such, whilecompliant damping is sometimes preferable (e.g. extremely rough terrain)but there are times when a more rigid damping mode is appropriate (e.g.on-highway). In one embodiment, the normally-open solenoid valve 220 maybe, at the user's discretion, partially or completely closed as itappears in FIG. 2A, to increase a damping rate of the damper and henceits rigidity.

In some instances, it may be desirable to increase the damping rate whenmoving a vehicle from off-road to on highway use. Off-road use oftenrequires a high degree of compliance to absorb shocks imparted by thewidely varying terrain. During highway use, particularly with long wheeltravel vehicles, often requires more rigid shock absorption is oftenrequired to allow a user to maintain control of a vehicle at higherspeeds. This may be especially true during cornering or braking.

In other instances, it is desirable to control/change dampeningcharacteristics in a rebound stroke of a damper. In one embodiment, thedamper operates with fluid traveling through the valves 210A, 210B, and220 during a rebound stroke. In FIG. 2B, both valves are also open tothe flow of return fluid opposite the flow arrow although the arrowshows compression flow. The reduced rebound dampening effects permit theshock absorber to extend faster than would otherwise be possible. Such asetting is important in an instance where terrain is encountered thatresults in a sudden “drop” of the ground away from a wheel or wheels ofthe vehicle. With the remotely-operable valve 220 in a closed position,additional dampening is added to that created by the rebounding damperpiston 105.

One embodiment comprises a four wheeled vehicle having solenoidvalve-equipped shock absorbers at each (of four) wheel. The valve 220(which in one embodiment is cable (mechanically), pneumatically, orhydraulically operated instead of solenoid operated) of each of thefront shock absorbers may be electrically connected with a linear motionactivated switch (such as that which operates an automotive brake light)that is activated in conjunction with the vehicle brake pedal. When thebrake pedal is depressed beyond a certain distance, correspondingusually to harder braking and hence potential for vehicle nose dive, theelectric switch connects a power supply to the normally open solenoid ineach of the front shocks, thereby closing the valve in those shocks. Assuch, the front shocks become more rigid during hard braking. Othermechanisms may be used to trigger the shocks such as accelerometers(e.g., tri-axial) for sensing pitch and roll of the vehicle andactivating, via a microprocessor, the appropriate solenoid valves foroptimum vehicle control.

In one embodiment, a vehicle steering column includes right turn andleft turn limit switches such that a hard turn in either directionactivates (e.g. closes valve 220) the solenoid on the shocks oppositethat direction (for example a hard right turn would cause more rigidshocks on the vehicle left side). Again, accelerometers in conjunctionwith a microprocessor and a switched power supply may perform thesolenoid activation function by sensing the actual g-force associatedwith the turn (or braking; or throttle acceleration for the rear shockactivation) and triggering the appropriate solenoid(s) at a presetthreshold g-force.

In one embodiment, a pressure intensifier damper arrangement may belocated within the fluid path of the remotely-operable valves 220 suchthat the valve 220 controls flow through that auxiliary damper which isthen additive with the valve assembly. In one embodiment the valveassembly comprises a pressure intensifier (such as described in U.S.Pat. No. 7,374,028 which is incorporated, entirely, herein byreference). The following is a description, with reference to FIGS. 3Aand 3B, of a pressure intensifier damper arrangement that is describedin U.S. Pat. No. 7,374,028.

Referring now to FIGS. 3A and 3B, the intensifier piston 350 of apressure intensifier damper arrangement is shown in the context ofembodiments relating to U.S. Pat. No. 7,374,028. A partition 310 issecured within the bore of the damper by a partition retaining ring 311.This partition 310 physically divides the hydraulic fluid into oneportion above the partition 310, and another portion below it. Thepartition 310 has a plurality of rebound flow ports 320 covered by acheck valve 330 which is lightly biased in contact with the partition310 by a relatively soft check valve spring 331. Additionally, thepartition 310 has a central compression flow port 340 which, in theposition illustrated in FIG. 3B, is blocked at its upper end by thesmall end of an intensifier piston 350.

The intensifier piston 350 is located within an intensifier housing 360,which can be integral with the damper cylinder 350 (as shown), or can bea separate structure sealed and retained within the bore of the dampercylinder 350. During upward movement of the intensifier piston 350 asoccurs during operation (to be described in detail further on), theintensifier piston 350 is prevented from exiting the intensifier housing360 by the intensifier retaining ring 351. The intensifier piston 350 issealingly engaged with the intensifier housing 360 at its upper (largediameter) end, as well as at its lower (smaller diameter) end. There isat least one vent port 370 which vents the space between the upper andlower seals of the intensifier piston 350 to outside atmosphericpressure. There is also at least one bi-directional flow port 380 whichpasses vertically through intensifier housing 360.

Still referring to FIGS. 3A and 3B, the pressure intensifier 350 of apressure intensifier damper arrangement is described in the followingparagraphs.

During a rebound stroke, the piston rod 320 is withdrawn from the dampercylinder 350, resulting in some amount of vacated volume toward thelower end of the damper cylinder 350. As described previously, thisresults in downward movement of the floating piston 360, as well as adownward flow of the hydraulic fluid 370 immediately below it. Sincedownward movement of the floating piston 360 reduces the space betweenthe floating piston 360 and the partition 410, and since hydraulic fluidis incompressible, hydraulic fluid flows down through the bi-directionalflow port(s) 480. It then flows down through the partition 410 via therebound flow port(s) 320. It does this by opening the check valve 330against the relatively light resistance of the check valve spring 431.

During a compression stroke, the piston rod 320 and the damping piston340 move further into the damper cylinder 350, thus displacing a volumeof the hydraulic fluid 370 equal to the volume of the additional lengthof the piston rod 320 which enters the damper cylinder 350. As describedpreviously, this results in an upward flow of the displaced volume ofhydraulic fluid, accommodated by an upward movement of the floatingpiston 360, which somewhat decreases the volume, and increases thepressure, in the internally-pressurized chamber 380. However, in orderto do so, the displaced volume of hydraulic fluid must first passthrough the partition 310. In accordance with the known principles ofhydraulic intensifiers, to achieve this, the fluid must create an upwardforce (pressure) at the lower (small) end of the intensifier piston 450which is sufficient to overcome the downward force (pressure) at theupper (large) end of the intensifier piston 350. To do so requires apressure at the lower end of the intensifier piston 450 that is greaterthan the pressure at the upper end of the intensifier piston 450 by amultiple approximately equal to the ratio of the cross-sectional area ofthe large end of the intensifier piston 450 to the cross-sectional areaof the compression flow port 440.

For simplicity, it is assumed that the diameter of the small end of theintensifier piston 450 is only slightly greater than the diameter of thecompression flow port 440. Thus, the annular contact area between theseparts is relatively quite small, and it can be said that, for flowthrough the compression flow port 440, a pressure is required at thelower end of the intensifier piston 450 that is greater than thepressure at the upper end of the intensifier piston 450 by a multipleapproximately equal to the ratio of the area of its large end divided bythe area of its small end.

This pressure differential (multiple) between the small end and largeend of the pressure intensifier 450 creates a compression damping effectin the damper.

Here is an example. Assume the diameter of the large end of theintensifier piston 450 is twice the diameter of the small end, and thusthat the ratio of their cross-sectional areas is 4:1. Assume thediameter of the piston rod 320 is O1/2″, and thus it has across-sectional area of about 0.2 square inches. Assume the dampingpiston 340 has traveled inward into the damper cylinder 350 somedistance (i.e., it is not fully-extended or “topped-out” against theseal head 330), as shown in FIG. 3A. Assume that the pressure of theinternally-pressurized chamber 380 above the floating piston is 100 psi.Assume static conditions, with the damping piston 340 not moving. Giventhese assumptions, and based on elementary principles, there is auniform pressure of 100 psi throughout the interior of the damper.Furthermore, it can be readily calculated that, under these staticconditions, the 100 psi internal pressure acting on the 0.2 square inchcross-sectional area of the piston rod 320 creates a 20-pound forcetending to extend the piston rod 320. In racing circles, this 20-poundforce is sometimes referred to as “static nose force”.

The above described static conditions. Now the compression dampingeffect produced by the intensifier piston 450 during a compressionstroke (inward movement of the piston rod 320) is described. Per basicprinciples, for an intensifier piston 450 with a cross-sectional arearatio of 4:1, a pressure of approximately 400 psi at the small end isrequired to overcome the 100 psi pressure at the large end (whichoriginates from the internally-pressurized chamber 380 above thefloating piston 360), in order to cause the intensifier piston 450 tomove upward, thus unblocking the compression flow port 440 and allowingupward flow of the hydraulic fluid 370 displaced by the inward movementof the piston rod 320.

For simplicity, it is assumed in the following discussion that thedamping piston 340 has several large thru-holes and no restrictivevalving (note that, actually, the exemplary embodiments of the presentinvention generally do incorporate restrictive valving on the dampingpiston 340 which does create compression damping forces). In otherwords, for purposes of clarity in describing the basic principles of thepresent embodiment, it is assumed here that the damping piston 340itself creates no compression damping forces. Now, the 400 psi pressurecreated at the small end of the intensifier piston 450 acts uniformlythroughout all portions of damper cylinder 350 below the intensifierpiston 450. Acting on the 0.2 square inch cross-sectional area of thepiston rod 320, it creates an 80-pound “dynamic nose force”. Thedifference between the previous 20-pound “static nose force” and this80-pound “dynamic nose force” is 60 pounds; this 60 pounds representsthe compression damping force produced by the present embodiment.Increasing the diameter and cross-sectional area of the piston rod 320,of course, would create an even greater damping force.

To further describe the intensifier piston 450, in terms of an exampleoperational application, in the following it will be assumed that theabove compression stroke continues inward for a distance sufficient tomove the floating piston 360 upward some amount and increase thepressure in the internally-pressurized chamber 380 from 100 psi to 150psi. This 150 psi pressure, of course, acts on the large end of theintensifier piston 450 and now approximately 600 psi pressure (basic 4:1ratio) is required at the small end of the intensifier piston 350 inorder for it to remain open, allowing continuation of the compressionstroke. With 600 psi now acting on the 0.2 square inch cross-sectionalarea of the piston rod 320 a 120-pound “dynamic nose force” is nowproduced. In other words, as the compression stroke continues and thedamping piston 340 and piston rod 320 travel further into the dampercylinder 350, the volume of hydraulic fluid displaced by the piston rod320 causes the floating piston 360 to move upward, which increases thepressure in the internally-pressurized chamber 380, which increases thecompression damping effect produced by the pressure intensifier damperarrangement, including the intensifier piston 450.

Put another way, the embodiment of U.S. Pat. No. 7,374,028 produces a“position-sensitive” compression damping effect, with the compressiondamping force increasing as the piston rod 320 and the damping piston340 moves further into the damper cylinder 350. The extent and degree ofthis position-sensitive effect is influenced by the pre-set volume ofthe internally-pressurized chamber 380 above the floating piston 360,relative to the diameter and maximum available travel of the piston rod320. If the pre-set volume of the internally-pressurized chamber 380 isrelatively large, the position-sensitive effect is reduced. If thepre-set volume is relatively small, the position-sensitive effect isincreased.

In one embodiment one or both of the valves 210, 220 comprise standardshim-type dampers. In one embodiment one or both of the valves 210, 220include an adjustable needle for low speed bleed. In one embodiment ablow off (e.g. checking poppet-type or shim) is included in one of theflow paths associated with the valves 210, 220.

As in other embodiments, the remotely-operable valve 220 may be solenoidor hydraulically operated or pneumatically operated or operated by anyother suitable motive mechanism. The valve may be operated remotely by aswitch or potentiometer located in the cockpit of a vehicle or attachedto appropriate operational parts of a vehicle for timely activation(e.g. brake pedal) or may be operated in response to input from amicroprocessor (e.g. calculating desired settings based on vehicleacceleration sensor data) or any suitable combination of activationmeans. In like manner, a controller for the adjustable pressure source(or for both the source and the valve) may be cockpit mounted and may bemanually adjustable or microprocessor controlled or both or selectivelyeither.

One embodiment comprises a four wheeled vehicle having solenoid valveequipped shock absorbers at each (of four) wheel. The solenoid valve(which in one embodiment is cable operated instead of solenoid operated)of each of the front shock absorbers may be electrically connected witha linear switch (such as that which operates an automotive brake light)that is activated in conjunction with the vehicle brake pedal. When thebrake pedal is depressed beyond a certain distance, correspondingusually to harder braking and hence potential for vehicle nose dive, theelectric switch connects a power supply to the normally open solenoid ineach of the front shocks thereby closing the damping fluid flow paths inthose shocks. As such the front shocks become more rigid during hardbraking. Other mechanisms may be used to trigger the shocks such asaccelerometers (e.g. tri-axial) for sensing pitch and roll of thevehicle and activating, via a microprocessor, the appropriate solenoidvalves for optimum vehicle control.

In one embodiment, a vehicle steering column includes right turn andleft turn limit switches such that a hard turn in either directionactivates (e.g. closes path 8SA) the solenoid on the shocks oppositethat direction (for example a hard right turn would cause more rigidshocks on the vehicle left side). Again, accelerometers in conjunctionwith a microprocessor and a switched power supply may perform thesolenoid activation function by sensing the actual g-force associatedwith the turn (or braking; or throttle acceleration for the rear shockactivation) and triggering the appropriate solenoid(s) at a presetthreshold g-force.

In one embodiment a remotely-operable valve 220 like the one describedabove is particularly useful with an on-/off-road vehicle. Thesevehicles can have as more than 20″ of shock absorber travel to permitthem to negotiate rough, uneven terrain at speed with usable shockabsorbing function. In off-road applications, compliant dampening isnecessary as the vehicle relies on its long travel suspension whenencountering often large off-road obstacles. Operating a vehicle withvery compliant, long travel suspension on a smooth road at higher speedscan be problematic due to the springiness/sponginess of the suspensionand corresponding vehicle handling problems associated with that (e.g.turning roll, braking pitch). Such compliance can cause reduced handlingcharacteristics and even loss of control. Such control issues can bepronounced when cornering at high speed as a compliant, long travelvehicle may tend to roll excessively. Similarly, such a vehicle maypitch and yaw excessively during braking and acceleration. With theremotely-operated bypass dampening and “lock out” described herein,dampening characteristics of a shock absorber can be completely changedfrom a compliantly dampened “springy” arrangement to a highly dampenedand “stiffer” (or fully locked out) system ideal for higher speeds on asmooth road. In one embodiment, where compression flow through thedamper piston 105 is completely blocked, closure of the valve 220 canresult in substantial “lock out” of the suspension (the suspension isrendered essentially rigid except for the movement of fluid throughshimmed valve 210). In one embodiment, where some compression flow isallowed through the damper piston 105 or the annular bypass 150, closureof the valve 220 results in a stiffer but still functional compressiondamper.

In addition to, or in lieu of, the simple, switch operated remotearrangement, the remotely-operable valve 220 can be operatedautomatically based upon one or more driving conditions such as vehiclespeed, damper rod speed, and damper rod position. One embodiment of thearrangement may automatically increase dampening in a shock absorber inthe event a damper rod reaches a certain velocity in its travel towardsthe bottom end of a damper at a predetermined speed of the vehicle. Inone embodiment, the damping (and control) increases in the event ofrapid operation (e.g. high damper rod velocity) of the damper to avoid abottoming out of the damper rod as well as a loss of control that canaccompany rapid compression of a shock absorber with a relative longamount of travel. In one embodiment, damping increases (e.g. closes orthrottles down the bypass) in the event that the damper rod velocity incompression is relatively low but the damper rod progresses past acertain point in the travel. Such configuration aids in stabilizing thevehicle against excessive low-rate suspension movement events such ascornering roll, braking and acceleration yaw and pitch and “g-out.”

While the examples illustrated relate to manual operation and automatedoperation based upon specific parameters, the remotely-operated valve220 (with or without valve 210) can be used in a variety of ways withmany different driving and road variables. In one example, the valve 220is controlled based upon vehicle speed in conjunction with the angularlocation of the vehicle's steering wheel. In this manner, by sensing thesteering wheel turn severity (angle of rotation), additional dampeningcan be applied to one damper or one set of dampers on one side of thevehicle (suitable for example to mitigate cornering roll) in the eventof a sharp turn at a relatively high speed. In another example, atransducer, such as an accelerometer, measures other aspects of thevehicle's suspension system, like axle force and/or moments applied tovarious parts of the vehicle, like steering tie damper rods, and directschange to the bypass valve positioning in response thereto. In anotherexample, the bypass can be controlled at least in part by a pressuretransducer measuring pressure in a vehicle tire and adding dampeningcharacteristics to some or all of the wheels in the event of, forexample, an increased or decreased pressure reading. In one embodiment,the damper bypass or bypasses are controlled in response to brakingpressure (as measured, for example, by a brake pedal sensor or brakefluid pressure sensor or accelerometer). In still another example, aparameter might include a gyroscopic mechanism that monitors vehicletrajectory and identifies a “spin-out” or other loss of controlcondition and adds and/or reduces dampening to some or all of thevehicle's dampers in the event of a loss of control to help the operatorof the vehicle to regain control.

While the foregoing is directed to certain embodiments, other andfurther embodiments may be implemented without departing from the scopeof the present technology, and the scope thereof is determined by theclaims that follow.

I claim:
 1. A vehicle damper comprising: a cylinder; a piston withinsaid cylinder; a working fluid within said cylinder; a reservoir influid communication with said cylinder via said working fluid, saidreservoir operable to receive said working fluid from said cylinder in acompression stroke; a flow path starting in said cylinder and ending insaid reservoir; a reservoir valve assembly disposed in said flow path,said reservoir valve assembly being configured for monitoring a flow ofsaid working fluid into a reservoir fluid portion of said reservoir,wherein said reservoir valve assembly comprises at least a base valve, aremotely-operable valve, and a third reservoir valve that is not saidbase valve and said remotely operable valve, said third reservoir valvedisposed in a first chamber, wherein said third reservoir valve ispositioned upstream of said remotely operable valve during saidcompression stroke, wherein said base valve provides a positive dampingresistance regardless of a compliant damping or a rigid damping pressurebeing applied separate from said positive damping resistance such thatsaid flow of said working fluid through said base valve occurs under allcircumstances, said remotely operable valve disposed in a second chamberadjacent said third reservoir valve, said remotely operable valveconfigured to control flow of said working fluid through said secondchamber, wherein said remotely-operable valve has an open position and aclosed position, wherein said open position allows at least a portion ofthe whole of said working fluid to by-pass said third reservoir valveand move through said remotely-operable valve to said base valve, saidremotely-operable valve operated automatically based on triggers relatedto conditions of a vehicle to which said remotely-operable valve iscoupled; and a pressure intensifier damper arrangement positioned withinsaid flow path starting in said cylinder and ending in said reservoir,such that said remotely-operable valve is enabled to control a flow ofsaid working fluid, thereby creating a damping effect, wherein saiddamping effect is additive to the results of a functioning of saidreservoir valve assembly.
 2. The vehicle damper of claim 1, wherein saidtriggers are selected from the group consisting of: brake pedaldepression, accelerometers, steering column motion, and g-force sensing.3. A vehicle damper comprising: a cylinder; a piston within saidcylinder; a working fluid within said cylinder; a reservoir in fluidcommunication with said cylinder via said working fluid, said reservoiroperable to receive said working fluid from said cylinder in acompression stroke; a flow path starting in said cylinder and ending insaid reservoir; a reservoir valve assembly disposed in said flow path,said reservoir valve assembly being configured for monitoring a flow ofsaid working fluid into a reservoir fluid portion of said reservoir,wherein said reservoir valve assembly comprises at least a base valve, aremotely-operable valve, and a third reservoir valve that is not saidbase valve and said remotely operable valve, said third reservoir valvedisposed in a first chamber, wherein said third reservoir valve ispositioned upstream of said remotely operable valve during saidcompression stroke, wherein said base valve provides a positive dampingresistance regardless of a compliant damping or a rigid damping pressurebeing applied separate from said positive damping resistance such thatsaid flow of said working fluid through said base valve occurs under allcircumstances, said remotely operable valve disposed in a second chamberadjacent said third reservoir valve, said remotely operable valveconfigured to control flow of said working fluid through said secondchamber, wherein said remotely-operable valve has an open position and aclosed position, wherein said open position allows at least a portion ofthe whole of said working fluid to by-pass said third reservoir valveand move through said remotely-operable valve to said base valve, saidremotely-operable valve operated automatically based on drivingconditions of a vehicle to which said remotely-operable valve iscoupled; and a pressure intensifier damper arrangement positioned withinsaid flow path starting in said cylinder and ending in said reservoir,such that said remotely-operable valve is enabled to control a flow ofsaid working fluid, thereby creating a damping effect, wherein saiddamping effect is additive to the results of a functioning of saidreservoir valve assembly.
 4. The vehicle damper of claim 3, wherein saiddriving conditions are selected from the group consisting of: vehiclespeed, damper rod velocity, and damper rod position.
 5. A vehicle dampercomprising: a cylinder; a piston within said cylinder; a working fluidwithin said cylinder; a reservoir in fluid communication with saidcylinder via said working fluid, said reservoir operable to receive saidworking fluid from said cylinder in a compression stroke; a flow pathstarting in said cylinder and ending in said reservoir; a reservoirvalve assembly disposed in said flow path, said reservoir valve assemblybeing configured for monitoring a flow of said working fluid into areservoir fluid portion of said reservoir, wherein said reservoir valveassembly comprises at least a base valve, a remotely-operable valve, anda third reservoir valve that is not said base valve and said remotelyoperable valve, said third reservoir valve disposed in a first chamber,wherein said third reservoir valve is positioned upstream of saidremotely operable valve during said compression stroke, wherein saidbase valve provides a positive damping resistance regardless of acompliant damping or a rigid damping pressure being applied separatefrom said positive damping resistance such that said flow of saidworking fluid through said base valve occurs under all circumstances,said remotely operable valve disposed in a second chamber adjacent saidthird reservoir valve, said remotely operable valve configured tocontrol flow of said working fluid through said second chamber, whereinsaid remotely-operable valve has an open position and a closed position,wherein said open position allows at least a portion of the whole ofsaid working fluid to by-pass said third reservoir valve and movethrough said remotely-operable valve to said base valve, saidremotely-operable valve operated automatically based on drivingvariables of a vehicle to which said remotely-operable valve is coupled;and a pressure intensifier damper arrangement positioned within saidflow path starting in said cylinder and ending in said reservoir, suchthat said remotely-operable valve is enabled to control a flow of saidworking fluid, thereby creating a damping effect, wherein said dampingeffect is additive to the results of a functioning of said reservoirvalve assembly.
 6. The vehicle damper of claim 5, wherein said drivingvariables are selected from the group consisting of: speed of saidvehicle in conjunction with angular location of a steering wheel of saidvehicle, aspects of a suspension system of said vehicle, pressure of atire of said vehicle, braking pressure of said vehicle, and trajectoryof said vehicle.
 7. A vehicle damper comprising: a cylinder; a pistonwithin said cylinder; a working fluid within said cylinder; a reservoirin fluid communication with said cylinder via said working fluid, saidreservoir operable to receive said working fluid from said cylinder in acompression stroke; a flow path starting in said cylinder and ending insaid reservoir; a reservoir valve assembly disposed in said flow path,said reservoir valve assembly being configured for monitoring a flow ofsaid working fluid into a reservoir fluid portion of said reservoir,wherein said reservoir valve assembly comprises at least a base valve, aremotely-operable valve, and a third reservoir valve that is not saidbase valve and said remotely operable valve, said third reservoir valvedisposed in a first chamber, wherein said third reservoir valve ispositioned upstream of said remotely operable valve during saidcompression stroke, wherein said base valve provides a positive dampingresistance regardless of a compliant damping or a rigid damping pressurebeing applied separate from said positive damping resistance such thatsaid flow of said working fluid through said base valve occurs under allcircumstances, said remotely operable valve disposed in a second chamberadjacent said third reservoir valve, said remotely operable valveconfigured to control flow of said working fluid through said secondchamber, wherein said remotely-operable valve has an open position and aclosed position, wherein said open position allows at least a portion ofthe whole of said working fluid to by-pass said third reservoir valveand move through said remotely-operable valve to said base valve; and apressure intensifier damper arrangement positioned within said flow pathstarting in said cylinder and ending in said reservoir, such that saidremotely-operable valve is enabled to control a flow of said workingfluid, thereby creating a damping effect, wherein said damping effect isadditive to the results of a functioning of said reservoir valveassembly.
 8. The vehicle damper of claim 7, wherein said pistoncomprises: at least one flow path through which said working fluidmeters from a first side of said piston to a second side of said piston.9. The vehicle damper of claim 8, further comprising: at least one shimcoupled with said at least one flow path, wherein said at least one shimat least partially obstructs said at least one flow path.
 10. Thevehicle damper of claim 9, wherein said at least one flow pathcomprises: a first flow path that is unrestricted, thereby allowingby-pass of said working fluid during said compression stroke.
 11. Thevehicle damper of claim 9, wherein said at least one flow pathcomprises: a second flow path that is restricted by said at least oneshim, thereby allowing a damping of a flow of said working fluid duringsaid compression stroke.
 12. The vehicle damper of claim 7, wherein saidcylinder comprises: a compression portion partially defined by a firstside of said piston; and a rebound chamber partially defined by a secondside of said piston; and a by-pass shut off valve positioned toward anend of said compression portion, wherein said by-pass shut off valve isbiased away from said end of said compression portion by a spring,wherein during said compression stroke, said piston moves toward saidby-pass shut off valve until a surface of said by-pass shut off valveabuts a radially outer portion of a leading surface facing saidcompression portion of said piston, at which point during saidcompression stroke, said surface of said by-pass shut off valve coversall ports located along an outer edge of said piston, wherein saidworking fluid remaining in said compression portion traverses saidpiston via ports located inward of said outer edge of said piston whichare not covered by said by-pass shut off valve.
 13. The vehicle damperof claim 12, wherein said by-pass shut off valve is movable with saidleading surface of said piston toward an end of said compression stroke.14. The vehicle damper of claim 7, further comprising: a compressionportion partially defined by a first side of said piston; a reboundchamber partially defined by a second side of said piston, said reboundchamber comprising a rebound chamber therein configured to hold saidworking fluid; a damper rod positioned within said cylinder, wherein afirst end of said damper rod is coupled to said piston that issurrounding said damper rod and configured to move with said damper rodduring said compression stroke or a rebound stroke; a central flow pathwithin said damper rod; a first set of radially outward directed flowpaths positioned within said damper rod and adjacent to said reboundchamber; and a second set of radially outward directed flow pathspositioned within said damper rod and adjacent to said piston, saidsecond set of radially outward directed flow paths traverse shim valvesbefore opening into a compression chamber of said compression portion,wherein during a rebound stroke, said working fluid within said reboundchamber flows into said first set of radially outward directed flowpaths as said damper rod moves outward from said compression portion,moves into said central flow path, and then moves to said second set ofradially outward directed flow paths.
 15. The vehicle damper of claim14, further comprising: a first sleeve having a diameter that is smallerthan a diameter of said cylinder and being within said rebound chamber,an inner surface of said first sleeve surrounding a portion of an outersurface of said damper rod; and a shut off valve positioned at a firstend of said first sleeve, wherein upon said first set of radiallyoutward directed flow paths being covered by said inner surface of saidfirst sleeve at said shut off valve, flow of said working fluid therethrough is terminated.
 16. The vehicle damper of claim 7, wherein saidreservoir comprises: a reservoir fluid portion configured for fillingwith said working fluid during said compression stroke; a floatingpiston; and a gas portion positioned in between and coupled to saidreservoir fluid portion and said floating piston, said gas portion beingcompressible as said reservoir fluid portion fills with said workingfluid.
 17. The vehicle damper of claim 16, wherein said vehicle dampercomprises: a gas valve located at a lower end of said reservoir, saidgas valve configured for adjusting a pressure of gas in said gas portionvia introduction of compressed air through said gas valve.
 18. Thevehicle damper of claim 7, wherein said reservoir valve assemblycomprises: a pathway leading from a fluid conduit into said reservoirfluid portion, wherein said fluid conduit houses said flow path betweensaid cylinder and said reservoir.
 19. The vehicle damper of claim 7,wherein said remotely-operable valve comprises: a seat; and a moveableplunger that is substantially sealable on said seat, wherein when saidmovable plunger is substantially sealed on said seat, saidremotely-operable valve is in a substantially closed position, therebypreventing at least a portion of said working fluid from passing therethrough.
 20. The vehicle damper of claim 19, further comprising: asolenoid coupled to said remotely-operable valve, said solenoidconfigured for receiving an electrical signal and causing a mechanicalmovement of said moveable plunger, wherein said mechanical movementcomprises a shift between a substantially open position and saidsubstantially closed position, wherein when said remotely-operable valveis in said substantially open position, said working fluid is capable offlowing through said remotely-operable valve.
 21. The vehicle damper ofclaim 20, wherein said solenoid comprises: a selectable strokefunctionality configured for partially closing and partially openingsaid remotely-operable valve, thereby at least one of permitting andrestricting flow of said working fluid there through without completelyopening or closing said remotely-operable valve.
 22. The vehicle damperof claim 20, wherein said electrical signal comprises: a sensed g-force.23. The vehicle damper of claim 19, further comprising: a cable coupledto said remotely-operable valve, said cable configured for receiving amechanically induced instruction and causing a mechanical movement ofsaid moveable plunger, wherein said mechanical movement comprises ashift between a substantially open position and said substantiallyclosed position, wherein when said remotely-operable valve is in saidsubstantially open position, said working fluid is capable of flowingthrough said remotely-operable valve.
 24. The vehicle damper of claim19, further comprising: a pneumatically functioning unit coupled to saidremotely-operable valve, said pneumatically functioning unit configuredfor causing a mechanical movement of said plunger, wherein saidmechanical movement comprises a shift between a substantially openposition and said substantially closed position, wherein when saidremotely-operable valve is in said substantially open position, saidworking fluid is capable of flowing through said remotely-operablevalve.
 25. The vehicle damper of claim 19, further comprising: ahydraulically functioning unit coupled to said remotely-operable valve,said hydraulically functioning unit configured for causing a mechanicalmovement of said plunger, wherein said mechanical movement comprises ashift between a substantially open position and said substantiallyclosed position, wherein when said remotely-operable valve is in saidsubstantially open position, said working fluid is capable of flowingthrough said remotely-operable valve.